Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability
The Arctic is an important component of the Earth’s climate system, and it is a region dynamically coupled to climate phenomena at lower latitudes, through both atmospheric and oceanic paths. The coupling has significant effects on the hydroclimate variability in the Arctic, including effects on sea...
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Georgia Institute of Technology
2015
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ftgeorgiatech:oai:repository.gatech.edu:1853/53869 2024-06-02T08:00:18+00:00 Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability Hegyi, Bradley Michael Deng, Yi Wang, Jingfeng Toma, Violeta Peng, Zhigang Black, Robert X. Earth and Atmospheric Sciences 2015-09-21T14:24:54Z application/pdf http://hdl.handle.net/1853/53869 en_US eng Georgia Institute of Technology http://hdl.handle.net/1853/53869 Arctic hydroclimate variability Large-scale atmospheric dynamics Connections between tropics and arctic climate Text Dissertation 2015 ftgeorgiatech 2024-05-06T11:21:29Z The Arctic is an important component of the Earth’s climate system, and it is a region dynamically coupled to climate phenomena at lower latitudes, through both atmospheric and oceanic paths. The coupling has significant effects on the hydroclimate variability in the Arctic, including effects on sea ice and Arctic precipitation. In this dissertation, we explore the coupling of the lower latitudes and the Arctic hydroclimate through atmospheric mechanisms with dynamical and thermodynamical components, with a focus on the following examples of variability: i) the decadal variability of boreal winter Arctic precipitation, ii) the variability of the strength of the stratospheric polar vortex in boreal winter, and iii) the initial melt of Arctic sea ice in late boreal spring. The goal of the research is to understand what drives the Arctic hydroclimate variability in each of these examples through improved knowledge of the mechanisms linking them to the tropics and Northern Hemisphere midlatitudes. In the first part of the analysis, we explore the mechanisms responsible for the decadal variability of boreal winter Arctic precipitation. We find that the decadal variability of cool-season Arctic precipitation is at least partly connected to decadal modulation of tropical central Pacific sea surface temperatures related to the El Niño-Southern Oscillation (ENSO). The modulation can be described as the oscillation between periods favoring central and eastern Pacific warming events [CPW and EPW, respectively], which are two common types of ENSO variability. By analyzing a collection of CPW and EPW events in reanalysis data, we establish the following connecting mechanism. First, the increase of central Pacific SSTs drive a Rossby wave train that destructively interferes with the zonal wavenumber 1 component of the background extratropical planetary wave in the subpolar region. Next, as a result of this interference, the magnitude of the vertical Rossby wave propagation from the troposphere to the stratosphere decreases ... Doctoral or Postdoctoral Thesis Arctic Sea ice Georgia Institute of Technology: SMARTech - Scholarly Materials and Research at Georgia Tech Arctic Pacific |
institution |
Open Polar |
collection |
Georgia Institute of Technology: SMARTech - Scholarly Materials and Research at Georgia Tech |
op_collection_id |
ftgeorgiatech |
language |
English |
topic |
Arctic hydroclimate variability Large-scale atmospheric dynamics Connections between tropics and arctic climate |
spellingShingle |
Arctic hydroclimate variability Large-scale atmospheric dynamics Connections between tropics and arctic climate Hegyi, Bradley Michael Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability |
topic_facet |
Arctic hydroclimate variability Large-scale atmospheric dynamics Connections between tropics and arctic climate |
description |
The Arctic is an important component of the Earth’s climate system, and it is a region dynamically coupled to climate phenomena at lower latitudes, through both atmospheric and oceanic paths. The coupling has significant effects on the hydroclimate variability in the Arctic, including effects on sea ice and Arctic precipitation. In this dissertation, we explore the coupling of the lower latitudes and the Arctic hydroclimate through atmospheric mechanisms with dynamical and thermodynamical components, with a focus on the following examples of variability: i) the decadal variability of boreal winter Arctic precipitation, ii) the variability of the strength of the stratospheric polar vortex in boreal winter, and iii) the initial melt of Arctic sea ice in late boreal spring. The goal of the research is to understand what drives the Arctic hydroclimate variability in each of these examples through improved knowledge of the mechanisms linking them to the tropics and Northern Hemisphere midlatitudes. In the first part of the analysis, we explore the mechanisms responsible for the decadal variability of boreal winter Arctic precipitation. We find that the decadal variability of cool-season Arctic precipitation is at least partly connected to decadal modulation of tropical central Pacific sea surface temperatures related to the El Niño-Southern Oscillation (ENSO). The modulation can be described as the oscillation between periods favoring central and eastern Pacific warming events [CPW and EPW, respectively], which are two common types of ENSO variability. By analyzing a collection of CPW and EPW events in reanalysis data, we establish the following connecting mechanism. First, the increase of central Pacific SSTs drive a Rossby wave train that destructively interferes with the zonal wavenumber 1 component of the background extratropical planetary wave in the subpolar region. Next, as a result of this interference, the magnitude of the vertical Rossby wave propagation from the troposphere to the stratosphere decreases ... |
author2 |
Deng, Yi Wang, Jingfeng Toma, Violeta Peng, Zhigang Black, Robert X. Earth and Atmospheric Sciences |
format |
Doctoral or Postdoctoral Thesis |
author |
Hegyi, Bradley Michael |
author_facet |
Hegyi, Bradley Michael |
author_sort |
Hegyi, Bradley Michael |
title |
Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability |
title_short |
Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability |
title_full |
Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability |
title_fullStr |
Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability |
title_full_unstemmed |
Dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability |
title_sort |
dynamical and thermodynamical influences of the tropics and midlatitudes on arctic hydroclimate variability |
publisher |
Georgia Institute of Technology |
publishDate |
2015 |
url |
http://hdl.handle.net/1853/53869 |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Arctic Sea ice |
genre_facet |
Arctic Sea ice |
op_relation |
http://hdl.handle.net/1853/53869 |
_version_ |
1800744290969714688 |